The National Cell Repository (NCR) was established over a decade ago to collect and maintain information and biological specimens on large numbers of genetically informative, phenotypically well-characterized families with multiple individuals affected with Alzheimer Disease (AD). These families have been successfully used to study the genetics of AD. Over the past decade there has been keen interest to identify the genes contributing to late onset (onset 60 years) AD (LOAD). To date, the important role of apolipoprotein E (APOE) has been delineated in families with LOAD. Clearly, other genes also contribute to late onset AD susceptibility. This supplemental application proposes to provide the resources critical to AD researchers that will allow the elucidation of LOAD susceptibility genes. To this end, the following specific aims are addressed in this supplemental application: 1) Ensure a resource of multiplex LOAD families recruited through Alzheimer Disease Centers (ADCs). a) Establish immortalized cell lines from all genetically informative family members. b) Assist ADCs to maintain contact with families to identify additional affected individuals and plan autopsies. 2) Establish a case control cohort recruited through the AIzheimer Disease Centers (ADCs). a) Isolate DNA from brain sections of LOAD cases previously ascertained through the ADCs. b) Establish immortalized cell lines from living cases and controls ascertained through the ADCs. 3) Obtain additional clinical data from previously recruited LOAD families already participating in the NCR. a) Complete telephone cognitive evaluation of all individuals over the age of 50 years. b) Obtain additional clinical information from informants regarding symptom progression of LOAD subjects. 4) Develop and maintain an internet resource (web page) to review available NCR resources.